When a peripheral device such as a wireless communication device or Global Positioning System (GPS) device is used in various portable terminal devices such as a cellular phone, an overall power consumption drastically increases in the portal terminal devices. Therefore, there is a technique where the operation of the peripheral device is deactivated to extend the battery life when, for example, the remaining capacity of the battery is reduced.
However, when the peripheral device is completely deactivated in a portable terminal device, there may be an application that cannot be used in the portable terminal device. For example, when the GPS or the Wi-Fi is deactivated, the portable terminal device may not be able to obtain the high-precision positional information. As a result, an application that uses the positional information such as, for example, a navigation system, becomes unavailable. In order to overcome the drawback, there is also a technique where the application running in the background is forcibly ended, rather than the peripheral device is ended, to reduce the power consumption. Even in this case, for example, when a schedule table application is activated to be executed in the foreground in order to confirm a schedule at a destination while navigating, the navigation application running in the background is forcibly ended to stop the navigation, thereby reducing the user convenience.
When a peripheral device is turned ON while an application running in the foreground of a portable terminal device is accessing the peripheral device, another irrelevant application running in the background at the same time may also be able to use the peripheral device. As a result, the battery consumption increases.
If a peripheral device that has a high power consumption is turned OFF or an application that has a high power consumption is forcibly ended uniformly when the remaining capacity of a battery becomes lower than a predetermined amount in order to increase the battery life of a portable terminal device, there is a concern that an application that a user wants to use may not be able to use the peripheral device.
The followings are reference documents.
[Document 1] Japanese National Publication of International Patent Application No 2004-530976
[Document 2] Japanese Laid-Open Patent Publication No. 2010-056700